With the modern day need for high speed mail handling systems, it has been found useful to transport envelopes along a mail handling feed path with a vertical orientation. This vertical orientation requires that many basic functions provided by prior machines, such as moistening and sealing of the envelope, require new mechanisms due to the differences in the mail handling orientation.
As a prelude to the moistening of envelope flaps, it is required that the flap be separated from the body portion of the envelope. With the vertical orientation of the moving piece of mail, it has been discovered that the flap of an envelope can be distended from the body of the letter by deforming the envelope about its flap end.
In a prior device, a force was applied to the back of an envelope causing the body of the envelope to flex. This flexing resulted in separating the flap from the letter. Such a device is shown in application Ser. No. 459,037; filed: Apr. 8, 1974, now U.S. Pat. No. 3,935,800.
This prior device posed several problems. In the first instance, it did not work properly for thick pieces of mail. An adequate flap separating force for thin envelopes, was too weak to break the back of heavier and thicker pieces of mail.
Secondly, this prior device was over thirteen inches long, making it difficult to fit into a small mail-handling machine.
The present inventive mechanism and method, can handle a wide range of envelope thicknesses. The envelope flap is more positively separated and distended by deforming the letter rather than applying an instantaneous force to it. The invention contemplates deforming the envelope in the bite of two axially adjacent rollers.
The present apparatus has many other advantages over the previous device, in that it is more compact; has fewer parts; is quieter; and simultaneously moves the envelope along the feed path, while distending the flap.